SUJET : LimeSurvey Integration

Hi,
I want to update another table when the user complete his survey , I did some search in lime survey and I have found this page limesurvey\application\controllers\admin\dataentry.php
in this method insert I have added my one code to update my external table, but it does not work! nothing happen !! may be it is not the right page!? can you tell me the right page please?
Thanks

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What I want to know is how can I use the function that update a survey when user click on "send" at the end of the survey ,as I have seen for each survey there is a table called `lime_tokens_XXXXXX` there is a field called "completed" it is "N "by default and when the user complete the survey this filed is updated with the date, so I want to know in which class or function or page this update is done ?